preparing colours

Icons are painted with egg-tempera. Normally no finished colours are used but pigments. The binder is egg yolk, which is mixed with water and a bit of apple vinegar (or stale beer or similar which prevents the egg from going bad too soon). Each pigment needs another amount of the binder, so one has to find out.

First the pigment and a bit of water is made into a mash, then the egg is added, until the colour is fine. The colour needs to be thin.